Addition Of Titanium Dioxide Research Articles

Effect of Food Additive E171 and Titanium Dioxide Nanoparticles (TiO2-NPs) on Caco-2 Colon Cancer Cells

Effect of Food Additive E171 and Titanium Dioxide Nanoparticles (TiO2-NPs) on Caco-2 Colon Cancer Cells

Investigating the Effect of UV Irradiation and TiO2 Addition on Heavy Metal Adsorption by Inverse Vulcanized Sulfur Polymers.

Organomercury contamination in wastewater is a longstanding global concern, prompting the establishment of the Mi-namata Convention in 2013, following the tragic Minamata Bay incident in Japan. Despite numerous proposed solutions, the development of an affordable and convenient adsorbent remains a challenge. Sulfur, being one of the most abundant elements globally, has shown promise in mercury adsorption in previous research. This study delves into the influence of light exposure on the process of mercury adsorption. Our findings reveal that exposure to UV-A wavelengths (315 nm - 400 nm), in combination with the addition of titanium dioxide (TiO2), enhances the adsorption capacity of a sulfur-rich polymer. The maximum observed adsorption capacity reached 47 mg/g under these conditions. Notably, the presence of TiO2 and UV exposure did not significantly impact the adsorption of inorganic mercury and gold.

Mathematical Modeling of Sorptive Extraction of Lithium Chloride from Lithium-containing Brine of the Aral Sea Region

Introduction The article presents the results of chemical and physicochemical analysis of initial lithium-containing hydromineral raw materials and sorbent based on bentonite clay with titanium oxide addition. Methods It is established that the mineral is montmorillonite group and kaolinite according to the results of the analysis of the microstructure and elemental composition of bentonitic clay of the Darbazinsky deposit. Brine is characterized by the change of lithium chloride content in the range of 403- 1001 mg/l. Physical and mechanical characteristics of the obtained sorbents based on bentonite clay and titanium oxide additive are characterized by a high mechanical strength of 5.31 MPa, density of up to 2,6 g/cm3, and specific surface area of 1572 cm2/g. The technological parameters of sorption extraction of lithium chloride from lithium-containing hydromineral raw materials were optimized using the system analysis “STATISTICA” developed by StatSoft company. It is established that to increase the rate of lithium chloride extraction from brine, it is necessary to maintain the rate of brine flow within 8 l/min at maximum humidity of solution output up to 43g/m3 on the basis of the obtained volumetric graphical dependencies. Results The microstructure of the used sorbents with titanium oxide addition up to 20% is characterized by the predominance of lithium chlorides, which are represented by heap-shaped, prismatic crystals. Conclusion The maximum amount of lithium chloride in the form of clusters of light-white crystals of tabular shape on the surface of the sorbent is observed at increasing the content of titanium oxide up to 40%.

Genome-wide DNA methylation sequencing reveals the involvement of ferroptosis in hepatotoxicity induced by dietary exposure to food-grade titanium dioxide

BackgroundFollowing the announcement by the European Food Safety Authority that the food additive titanium dioxide (E 171) is unsafe for human consumption, and the subsequent ban by the European Commission, concerns have intensified over the potential risks E 171 poses to human vital organs. The liver is the main organ for food-grade nanoparticle metabolism. It is increasingly being found that epigenetic changes may play an important role in nanomaterial-induced hepatotoxicity. However, the profound effects of E 171 on the liver, especially at the epigenetic level, remain largely unknown.MethodsMice were exposed orally to human-relevant doses of two types of E 171 mixed in diet for 28 and/or 84 days. Conventional toxicology and global DNA methylation analyses were performed to assess E 171-induced hepatotoxicity and epigenetic changes. Whole genome bisulfite sequencing and further ferroptosis protein detection were used to reveal E 171-induced changes in liver methylation profiles and toxic mechanisms.ResultsExposed to E 171 for 28 and/or 84 days resulted in reduced global DNA methylation and hydroxymethylation in the liver of mice. E 171 exposure for 84 days elicited inflammation and damage in the mouse liver, whereas 28-day exposure did not. Whole-genome DNA methylation sequencing disclosed substantial methylation alterations at the CG and non-CG sites of the liver DNA in mice exposed to E 171 for 84 days. Mechanistic analysis of the DNA methylation alterations indicated that ferroptosis contributed to the liver toxicity induced by E 171. E 171-induced DNA methylation changes triggered NCOA4-mediated ferritinophagy, attenuated the protein levels of GPX4, FTH1, and FTL in the liver, and thereby caused ferroptosis.ConclusionsLong-term oral exposure to E 171 triggers hepatotoxicity and induces methylation changes in both CG and non-CG sites of liver DNA. These epigenetic alterations activate ferroptosis in the liver through NCOA4-mediated ferritinophagy, highlighting the role of DNA methylation and ferroptosis in the potential toxicity caused by E 171 in vivo.

Are we approaching the development of a novel calcium phosphate-based bioceramic dental material?

ObjectivesDevelop a sustainable bovine hydroxyapatite dental ceramic with the addition of titanium dioxide (TiO2) nanoparticles (5 % and 8 % by weight), analyzing the outcome of this addition to the microstructure, as well as its mechanical and chemical properties, in order to evaluate whether they satisfy the International Organization for Standardization (ISO) 6872:2015 for dental ceramics or not. MethodsDisks were obtained through uniaxial followed by isostatic pressing from bovine hydroxyapatite powder and TiO2 nanoparticles and sintered at 1300ºC for 2 h. Three experimental groups were developed (HA, HA+5 %TiO2 and HA+8 %TiO2) and subjected to X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), indentation fracture (IF), biaxial flexural strength (BFS) and chemical solubility test. ResultsXRD revealed, for HA group, the appearance of a peak corresponding to b-tricalcium phosphate (ß-TCP). For HA+ 5 %TiO2 and HA+ 8 %TiO2, the entire composition was converted into ß-TCP and calcium titanate (CaTiO3). The SEM images showed a dense ceramic matrix and a uniform distribution of another phase in groups with TiO2 nanoparticles. HA+ 5 %TiO2 (1.40 ± 0.18 MPa.m1/2) and HA+ 8 %TiO2 (1.32 ± 0.18 MPa.m1/2) showed significantly higher fracture toughness values than HA (0.67 ± 0.09 MPa.m1/2). HA showed significantly higher characteristic stress (295.8 MPa) in comparison to groups with 5 % (235.1 MPa) and 8 % (214.4 MPa) TiO2 nanoparticles. Differences were not observed between the Weibull modulus values. The solubility results indicated that all experimental ceramics were above the 2000 ug/cm2 limit set by the ISO 6872:2015. SignificanceThis study proposed the development and characterization of a new ceramic for dental prosthesis made from HA extracted from bovine bones, with the intention of reusing these solids waste and transforming them into a sustainable and low-cost material. Although the experimental calcium phosphate ceramic with additions of 5 % and 8 % of TiO2 achieved desirable mechanical properties, the chemical solubility values were very high.

Investigating the Effects of PU-Based Back-Coating with Boric Acid and Titanium Dioxide Additives on Flame Retardancy Levels and Comfort Properties of 100% Cotton Denim Fabric

Abstract This study aimed to develop a cost-effective and resource-efficient application to enhance the thermal stability, flame retardancy, self-cleaning, and antibacterial properties of cotton denim fabrics through a single-step, flexible, and simple polyurethane (PU) based back-coating method, ultimately increasing the use of denim fabrics in daily and work clothes thanks to the increased functionality. This method utilizes boric acid (H3BO3) and a binary composite of H3BO3-titanium dioxide (TiO2) as functional additives while considering comfort parameters. Limiting oxygen index (LOI) and vertical burning tests were conducted to explore the thermal stability and flame retardancy of the samples, while assessments of air permeability, water vapour permeability, thermal resistance, and thermal absorptivity were performed to investigate the comfort properties. Comparing two kinds of back-coated denim fabrics, H3BO3-TiO2 back-coated cotton fabric showed the best flame retardancy with the lowest char length (45 mm) and highest LOI (27%). The air permeability values of back-coated fabrics decreased by approximately half compared to the untreated denim fabric. Although the water vapour permeability values decreased, they were less affected by the coating. Coating application reduced thermal conductivity and thermal absorbency, resulting in more thermally resistant denim fabric. This study demonstrates the potential utility of a PU-based coating incorporating TiO2 and H3BO3 on traditional cotton denim fabrics to enhance flame resistance while minimizing any adverse effects on the overall thermal comfort of the fabric.

Effect of TiO₂ Addition on Elastic Moduli, Optical Bandgap, and Electrical Conductivity of xTiO₂-(0.30-x)Bi₂O₃-0.10ZnO-0.60TeO₂ Glassy Systems with Improved Thermal Stability

Glassy systems with the chemical composition xTiO2-(0.30-x)Bi2O3-0.10ZnO-0.60TeO2 (x = 0.05,0.10,0.15,0.20) have been synthesized using the melt quench approach. Numerous physical, electrical, optical, and other features of elastic moduli have been evaluated as titanium oxide concentration rises. The amorphous properties of the materials under inspection are displayed in the XRD pattern. As the concentration of arsenic rises, the glasses' density falls from 4.18 to 3.96 g/cm3, while their molar volume rises from 48.21 to 53.06 cm3mol-1. The elastic properties of the synthesized glasses, such as the shear (S) and longitudinal (L) stresses, bulk modulus (K), Young's modulus (Y), and Poisson's ratio (Pr), have all been measured using the measured values of the ultrasonic velocities. The increase in elastic moduli values showed that the materials' elastic qualities have been improved. The results are explained in terms of a significant structural alteration caused by molecular rearrangement, which controls the physical properties of the glass. The addition of titanium oxide is shown to cause a decrease in Urbach energies from 0.96 to 0.67 eV, which results in an increase in the optical band gap energies from 2.96 to 3.33 eV. DSC thermogram measurements reveal mechanically enhanced and thermally stable materials with potential for use in semiconducting devices.

Sn99Ag0.3Cu0.7–TiO2 composite solder joints and their influence on thermal parameters of power components

PurposeThis paper aims to investigate the influence of composite solder joint preparation on the thermal properties of metal-oxide-semiconductor field-effect transistors (MOSFETs) and the mechanical strength of the soldered joint.Design/methodology/approachReinforced composite solder joints with the addition of titanium oxide nanopowder (TiO2) were prepared. The reference alloy was Sn99Ag0.3Cu0.7. Reinforced joints differed in the weight percentage of TiO2, ranging from 0.125 to 1.0 Wt.%. Two types of components were used for the tests. The resistor in the 0805 package was used for mechanical strength tests, where the component was soldered to the FR4 substrate. For thermal parameters measurements, a power element MOSFET in a TO-263 package was used, which was soldered to a metal core printed circuit board (PCB) substrate. Components were soldered in batch IR oven.FindingsShear tests showed that the addition of titanium oxide does not significantly increase the resistance of the solder joint to mechanical damage. Titanium oxide addition was shown to not considerably influence the soldered joint’s mechanical strength compared to reference samples when soldered in batch ovens. Thermal resistance Rthj-a of MOSFETs depends on TiO2 concentration in the composite solder joint reaching the minimum Rthj at 0.25 Wt.% of TiO2.Research limitations/implicationsMechanical strength: TiO2 reinforcement shows minimal impact on mechanical strength, suggesting altered liquidus temperature and microstructure, requiring further investigation. Thermal performance: thermal parameters vary with TiO2 concentration, with optimal performance at 0.25 Wt.%. Experimental validation is crucial for practical application. Experimental confirmation: validation of optimal concentrations is essential for accurate assessment and real-world application. Soldering method influence: batch oven soldering may affect mechanical strength, necessitating exploration of alternative methods. Thermal vs mechanical enhancement: while TiO2 does not notably enhance mechanical strength, it improves thermal properties, highlighting the need for balanced design in power semiconductor assembly.Practical implicationsIncorporating TiO2 enhances thermal properties in power semiconductor assembly. Optimal concentration balancing thermal performance and mechanical strength must be determined experimentally. Batch oven soldering may influence mechanical strength, requiring evaluation of alternative techniques. TiO2 composite solder joints offer promise in power electronics for efficient heat dissipation. Microstructural analysis can optimize solder joint design and performance. Rigorous quality control during soldering ensures consistent thermal performance and mitigates negative effects on mechanical strength.Social implicationsThe integration of TiO2 reinforcement in solder joints impacts thermal properties crucial for power semiconductor assembly. However, its influence on mechanical strength is limited, potentially affecting product reliability. Understanding these effects necessitates collaborative efforts between researchers and industry stakeholders to develop robust soldering techniques. Ensuring optimal TiO2 concentration through experimental validation is essential to maintain product integrity and safety standards. Additionally, dissemination of research findings and best practices can empower manufacturers to make informed decisions, fostering innovation and sustainability in electronic manufacturing processes. Ultimately, addressing these social implications promotes technological advancement while prioritizing consumer trust and product quality in the electronics industry.Originality/valueThe research shows the importance of the soldering technology used to assemble MOSFET devices.

Improving frictional and insulation performance with silica-coated titanium dioxide additives in grease

PurposeThe purpose of this study was to synthesize composite nanoparticles (TiO2@SiO2) via the chemical deposition method and investigate their efficacy as additives in polytetrafluoroethylene (PTFE) lubricating grease. The focus was on examining the frictional and conductive properties of the TiO2@SiO2 grease using a friction tester.Design/methodology/approachComposite nanoparticles (TiO2@SiO2) were synthesized using the chemical deposition method and incorporated into PTFE grease. Frictional and conductive properties were evaluated using a friction tester. Surface morphology and chemical composition of wear tracks were analyzed using scanning electron microscope and X-ray photoelectron spectroscopy, respectively.FindingsIncorporating TiO2@SiO2 at a mass fraction of 1 Wt.% led to a significant reduction in friction coefficient and wear width. The wear depth exhibited a remarkable decrease of 260%, while the contact resistance reached its peak value. This improvement in tribological properties could be attributed to the presence of TiO2@SiO2, where TiO2 served as the core and SiO2 as the shell during the friction process. The high hardness of the SiO2 shell contributed to enhanced load-bearing capacity. In addition, the exceptional insulation properties of SiO2 demonstrated excellent electron-capturing capabilities, resulting in improved friction and insulation performance of the TiO2@SiO2 lubricating grease.Originality/valueThis study demonstrates the potential of TiO2@SiO2 composite nanoparticles as additives in lubricating greases, offering improved friction and insulation performance. The findings provide insights into the design of advanced lubricating materials with enhanced tribological properties and insulation capacity, contributing to the development of more efficient and durable lubrication systems.

Research on preparation and performance tests of the fire retardant coatings for special functionalized wires and cables

This study aimed to produce a new potential intumescent flame retardant system through the addition of titanium dioxide and alumina-silica fiber based on optimizing the traditional ammonium polyphosphate (APP) / melamine (MEL) / pentaerythritol (PER) intumescent flame retardant formula. The flame retardant capacity and the physical properties were fully analyzed and discussed. The produced flame retardant coating could resist the rapid rise in 1100 of high flame temperature, whereas 40 exceeded the national standards. Thus, the produced flame retardant coating in this study could be potentially further applied to the cables and wires that are frequently needed in petroleum, telecommunication, military, tunnel, and electric uses.

The Effect of the Addition of Titanium Dioxide on Silicone Self-Adhesive Tapes

The investigation aimed to delve into the intricate relationship between the presence of titanium dioxide and the resulting alterations in the adhesive's behavior under different conditions. The focus extended beyond mere observation to understand how these additives interact with the adhesive matrix, potentially imparting beneficial attributes. Notably, the study delved into the optimization of thermal stability, the extension of the adhesive's functional lifespan, and the mitigation of shrinkage tendencies. This multi-faceted approach involved comprehensive testing, analysis, and comparison of adhesive samples containing varying additions of titanium dioxide.

Determination of the flexural properties of additively manufactured polyamide 12 components with antimicrobial titanium dioxide additives

AbstractAntibacterial properties of components are increasingly becoming an important challenge in material development especially in polymer technology. A well‐known additive with which an antibacterial effect can be achieved is the metal oxide titanium dioxide. The aim of this research work was to investigate possible influences on the flexural properties of additively manufactured components resulting from the addition of titanium dioxide as an antimicrobial additive. Compounds with 5 %, 10 % and 15 % titanium dioxide and polyamide 12 as matrix material were produced. Three‐point bending test specimens were fabricated out of these compounds, anaylsed and the results were compared with specimens made of virgin polyamide 12. The investigations show a general loss in ductility compared to the virgin polyamide 12. A comparison of the different titanium dioxide contents shows no clear change in the flexural stress at conventional bending. The flexural strain at break seems to decrease for higher titanium dioxide contents.

Antibacterial Properties and Shear Bond Strength of Titanium Dioxide Nanoparticles Incorporated into an Orthodontic Adhesive: A Systematic Review.

The present review was conducted to test whether the addition of titanium dioxide (TiO2) nanoparticles (NPs) within orthodontic bracket adhesives would alter their properties and assess their antimicrobial activity against cariogenic microorganisms in addition to noteworthy mechanical properties. Using predetermined inclusion criteria, an electronic search was conducted using Dissertations and Thesis Global, the Web of Science, Cochrane, Scopus, and Medline/PubMed. Specific terms were utilized while searching the database. Only seven of the 10 included studies assessed shear bond strength (SBS). The mean SBS among the control group varied from 9.43 ± 3.03 MPa to 34.4 ± 6.7 MPa in the included studies, while in the experimental group, it varied from 6.33 ± 1.51 MPa to 25.05 ± 0.5 MPa. Antibacterial activity was assessed in five of the 10 included studies using TiO2 NPs, which could easily diffuse through bacterial media to form the growth inhibition zone. Antibacterial NPs added to orthodontic adhesives at a concentration of 1-5 wt% inhibit bacterial growth and have no effect on bond strength. D Tivanani MVD, Mulakala V, Keerthi VS. Antibacterial Properties and Shear Bond Strength of Titanium Dioxide Nanoparticles Incorporated into an Orthodontic Adhesive: A Systematic Review. Int J Clin Pediatr Dent 2024;17(1):102-108.

The Tribological and Rheological Properties of Vegetable Lubricating Grease Modified of TiO2 Nanoparticles

The article presents the results of tribological and rheological research of lubricating composition modified of various content of titanium dioxide. The analysis of anti-wear properties during the test for the tested lubricating composition indicates a significant change in this parameters for lubricants modified of titanium dioxide. A change of the value of evaluated tribological parameters leads to change in the structure of the composition carried out tests and a change in the effectiveness of the tribological protection of the tribosystem. The content of the thickener, base of oil and additive in the lubricant structure affects the level of the anti-wear properties, as evidenced by the results obtained during the tribological tests presented in this article. Also, the tribological tests were carried out with the T-02 four-ball machine for the base grease, i.e. without a modifying additive, and compared with the results obtained for lubricating greases modified with various amounts of titanium dioxide. The results of welding load, limiting pressure of seizure, scuffing load, limiting load of scuffing and limiting load of wear were used to evaluate the tribological properties. Based on the results of tribological tests of vegetable lubricating compositions, it was found, that the addition of titanium dioxide changed the anti-wear and anti-seizure properties of the vegetable lubricating compositions under study. The introduction of various amount of titanium dioxide caused an increase of dynamic viscosity at lower shear rates and significant changes of viscosity in the low temperatures. The introduction of modifier led to the decrease of yield point value from content value of used additive of tested lubricating compositions.

Effect of chronic prenatal exposure to the food additive titanium dioxide E171 on respiratory activity in newborn mice.

Nanoparticles (NPs) possess unique properties that make their use valuable in all industries. Titanium dioxide (TiO2) NPs are extensively used as a white pigment in food (labeled under the European number E171) and personal care products, which creates a significant potential for chronic consumer exposure. Concerns about the potential toxic effects of TiO2 NPs have arisen, particularly in vulnerable populations, including pregnant women and infants. Recently, human materno-fetal transfer of E171 was demonstrated, and simultaneously, we reported that chronic prenatal exposure to reference P25 TiO2 NPs was found to alter the developing respiratory neural networks. In this study, using whole body plethysmography from postnatal day (P) 0 to P7, we assessed the respiratory function of newborn mice born to mothers fed with E171 during pregnancy. We also evaluated the potential alterations to respiratory centers by using brainstem-spinal cord electrophysiological recordings from P0 to P6. Our study reveals that E171-prenatally exposed animals displayed an abnormally elevated breathing rate from P3 onwards. From P5 to P6, the respiratory-related burst frequency generated by the isolated brainstem-spinal cord preparations was significantly higher in E171-exposed animals than in non-exposed animals. These findings demonstrate prenatal toxicity of E171 to the developing respiratory function and may contribute to policy-making regarding the use of TiO2 NPs.

Genotoxicity evaluation of food additive titanium dioxide using a battery of standard in vivo tests

The increasing use of titanium dioxide (TiO2) nanoparticles (NPs) has raised concern about the safety of food additive TiO2. TiO2 has been considered no longer safe by EFSA due to concerns over genotoxicity, however, there are conflicting opinions upon the safety of TiO2 as a food additive, and the number of in vivo genotoxicity studies conducted on food additive TiO2 was limited. In order to investigate the potential genotoxicity of food additive TiO2, we evaluated the genotoxicity of a commercial food additive TiO2 (average size of 135.54 ± 41.01 nm, range from 60.83 to 230.16 nm, NPs account for 30% by number) using a battery of standard in vivo tests, including mammalian erythrocyte micronucleus test, mammalian bone marrow chromosomal aberration test and in vivo mammalian alkaline comet test. After 15 days of consecutive intragastric administration at doses of 250, 500, and 1000 mg/kgBW, food additive TiO2 neither increased the frequencies of bone marrow micronuclei or chromosomal aberration in mice, nor induced DNA strand breakage in rat liver cells. These results indicate that under the condition of this study, food additive TiO2 does not have genotoxic potential although it contains a fraction of NPs.

Effect of the titanium-dioxide addition on the structural, dielectric, and mechanical properties of different cement-based mortars with corundum aggregate

The primary objective of this study was to look into the role of titanium dioxide in the production of corundum-based mortars, with a focus on finding the optimal mortar composition for achieving improved mechanical and dielectric performances. Changes in the mix design (different binders, different additive dosages), as well as their effects on the hydration pathway, chemical bonds, phase modifications, and microstructure, were examined. These findings were then correlated to the designed mortars' mechanical strengths and dielectric properties. Experimental mortars were produced with binders made from ordinary Portland cement, high alumina cement, and their mixtures, and corundum as aggregate. Titanium dioxide was employed as an additive (3 and 5wt.%). Nine different mortars were submitted for comprehensive mineralogical and microstructural characterization upon curing and solidification. The compressive and flexural strengths were monitored throughout the 28-day period. The dielectric constant (εr), dielectric loss tangent (tanδ), and electrical resistivity (ρ) were measured over a frequency range of 100Hz to 1MHz. XRD analysis highlighted the appearance of mayenite as a dielectric-prone phase in the samples doped with titanium dioxide. Differential thermal analysis and FTIR spectroscopy identified a higher amount of extra-low crystalline phase in OPC and HAC mortars with TiO2 addition, which accelerated hydration mechanisms, created a surplus of hydration products and made a more compact cement matrix. TiO2 added in 3wt.% amount led to higher mechanical strengths in OPC-based mortars, while it improved the dielectric properties of HAC mortars.

First highly effective non-catalytic nitrobenzene reduction in UV/dithionite system with aniline production – Advanced reduction process (ARP) approach

Advanced reduction processes (ARPs) are currently intensively investigated as an alternative to Advanced Oxidation Processes (AOPs). The study presents efficient reduction of nitrobenzene under non-catalytic conditions through reaction with free radicals having reductive potential. Effective conversion of nitrobenzene in a model wastewater solution, was obtained for sodium dithionite (SDT)/ dithionite (DTN). The developed process provide a nitrobenzene reduction efficiency of > 99.9 % within 10 min under neutral conditions, ambient temperature, with a molar ratio of reductant to pollutant (rred) of 3. Additional UV radiation lowered by 10 % the dose of DTN. Interestingly, addition of titanium dioxide (TiO2) as a photocatalyst did not show a positive effect. An extremely significant conclusion of this study is the observed excellent resistance of the reaction system to the negative influence of inorganic anions, with a reduction in efficiency in the following order: CO32-22%>NO3-6%>SO42-2%>Cl-2%>NO2-<1%>S2O32-<1%>N3-<1% and dissolved organic matter (DOM) (<13%). The study showed that the process works effectively across the pH range from 3 to 12. Studies on the reaction mechanism revealed that sulfur dioxide anion radical (SO2∙-)) was responsible for the main reduction effect. The main product of nitrobenzene reduction was aniline (>99.9 %). The total cost of purification process was USD 0.77/m3. The high efficiency, short process time, low cost, and lack of need for complicated equipment make this developed process potentially widely applicable in the industry. The developed method for the reduction of nitrobenzene to aniline is the first non-catalytic method with such high efficiency and without the formation of intermediate reaction products.

Numerical Investigation of Thermal Behavior of Nano-Phase Change Materials Due to Non-Newtonian Fluid Flow in the Porous Finned Tube

In this study, the melting of different types of phase change materials in a heat exchanger, the effect of porosity, triangular fins, and the addition of aluminum oxide, titanium oxide, and copper oxide, nanoparticles on the thermal behavior of four types of materials are studied numerically. The enthalpy porosity method is used during the melting process. The main heat transfer fluid is non-Newtonian and the tube is filled with a porous medium. The nanoparticle volume fraction is varied from 0 to 10%, the fin height is considered from 0 to 6 mm, and the porosity is considered equal to 0.8991, 0.9138, 0.9486, and 1. Based on the results, RT26 has the lowest melting time, and RT35 has the longest melting time with an increasing percentage of approximately 250%. The addition of fins and nanoparticles leads to an increase in the liquid fraction. The full charge time of materials with the addition of aluminum oxide nanoparticles is slightly less than other nanoparticles. Furthermore, the effect of using fins is greater than the effect of the addition of nanoparticles to reduce the melting time. Also, the maximum increase in the liquid fraction is approximately 30% due to the absence of a porous medium.

Effects of Incorporation of Titanium Dioxide Nanoparticles on Mechanical Properties of Conventional Glass Ionomer Cement

Background: Due to the poor mechanical properties of Glass Ionomer Cement (GICs), their use is limited to low stress-bearing areas. This study aimed to assess the effect of the addition of Titanium Dioxide (TiO2) nanoparticles on the flexural strength and surface hardness of GIC. Methods: In this in vitro study, 3, 5, and 10 wt.% TiO2 nanoparticles were added to Fuji II conventional GIC powder. The purity and composition of the as-synthesized titania were investigated by using XRD and FT-IR tools. The homogeneity of powder particles within the used matrix was evaluated under a Scanning Electron Microscope (SEM). Results: The SEM micrographs confirmed the homogenous mixing of TiO2 nanoparticles with GIC powder. Conclusion: Nevertheless, the flexural strength of experimental groups was not significantly different from that of the control group (p=0.384). However, the surface hardness of experimental groups was decreased in comparison with that of the control group (p&lt;0.001).